Congrats on the new garter. The most important consideration in setting up your enclosure is to regulate all heating devices with a thermostat. It's paramount in safeguarding the snake from burns and improper temperatures. So I would disconnect the heat pad until you can get a reliable thermostat. They can be found on Amazon and are fairly inexpensive for the basic ones. The reason you are not seeing much waste is bc babies usually use up most of their food for growth especially if they are fed conservatively. I still would be very vigilant in looking for excrement and urates/urine spots in the corners and in the hides of the enclosure. Also the water dish is a common place for snakes to relieve themselves. Feeding baby garters should be every three to four days unless they are having feeding issues. They have high metabolic rates and burn food stores rapidly. A varied diet is best but the individual snake will let you know what they like best. Pink mice f/t, fresh cut up market fish, f/t Sally's silversides sliced to a appropriate size is a safe bet also. My checkereds all love cut up live Canadian Nightcrawlers, especially the babies.